IT201600080088A1 - MACHINE FOR THE PREPARATION OF BEVERAGES, IN PARTICULAR ESPRESSO COFFEE, VALVE AND VALVE GROUP CAN BE USED IN SUCH A MACHINE - Google Patents

Description

"Machine for the preparation of beverages, in particular espresso coffee, valve and valve unit that can be used in this machine"

DESCRIPTION

Field of the invention

The present invention generally relates to machines for preparing beverages, in particular espresso coffee. The invention has been developed with particular reference to the discharge valves for machines of the indicated type comprising a fluid actuator, particularly a hydraulic actuator used to operate an infusion unit in closing.

State of the art

Various machines for the preparation of beverages, such as for example coffee, have an infusion unit which comprises at least two parts, of which at least one is movable relative to the other. The two parts of the group are capable of defining an infusion chamber between them, when they are in a closed or close position. A first part is configured for the introduction into the infusion chamber of the water necessary for the preparation of the beverage. The second part, on the other hand, defines a housing, configured to receive a precursor of the beverage, such as for example a dose of ground coffee, or a capsule or a pod in filter paper containing this dose of precursor, and allow the beverage to be dispensed from the infusion chamber.

These machines are usually equipped with an actuation system aimed at causing the movement of at least one of the two parts of the infusion group, between an open or spaced position and the aforesaid closed or close position. In the open position, the precursor or the capsule or the pod can be positioned in the second part of the group, while in the closed position the water can be fed to the group, for the preparation and dispensing of the drink. After dispensing, the two parts of the group can be returned to the open position, for the evacuation of the precursor or capsule or pod.

The aforesaid actuation system is often of the manual or electromechanical type. Machines have also been proposed in which the actuation system bases its operation on a fluid actuator, particularly a hydraulic piston actuator, which is fed using the same pump of the machine. In short, at the start of a beverage preparation cycle, the pump draws water from the relative tank, forcing it in parallel towards the infusion unit and towards the fluid actuator. The hydraulic circuit of the machine is configured in such a way that the actuator is powered before the infusion group, so that the group itself is brought into its closed position before the actual infusion starts.

A machine of this type is known for example from CN 202875026 U, in which the part of the unit operated by the hydraulic actuator essentially comprises an injector device provided with tips for drilling an end wall of a capsule. The second part of the unit is a drawer container, which can be manually removed from a predetermined position, defined by the machine structure, which delimits a capsule reception space. The drawer container is also provided with tips for perforating a second end wall of the capsule, as well as with a beverage dispensing nozzle.

The Applicant has in the past proposed machines made according to the technique described in the aforementioned prior document, additionally provided with a discharge valve intended to allow the return to the tank of the water machine used each time to feed the fluid actuator.

In these machines proposed by the Applicant - and as explained in detail below in relation to the attached figure 1 - the discharge valve is a two-way, two-position solenoid valve, normally open. In operation, when the beverage has been dispensed, the water contained in the part of the hydraulic circuit relating to the fluid actuator supply is discharged through this solenoid valve: for this purpose, a control unit de-energizes the solenoid valve, thereby opening a drainage passage which allows this water to return to the tank of the machine.

This measure is mainly adopted to avoid the consumption of clean water, as well as to ensure that the fluid actuator allows the return of the mobile part of the brewing group in its open or spaced position with respect to the other part of the group, even under the action of springs or the like.

The known solution indicated above works very well, but is rather expensive, in view of the fact that the discharge valve is a solenoid valve, which must be connected to the control unit of the machine by means of a suitable electric command line. The control unit must also be provided with suitable components for driving such a valve.

Consider in addition the disadvantage deriving from the use of an electromagnetic solenoid, which is entrusted with the operation of the shutter of the discharge valve: it is known that the mechanical forces available for this operation vary in proportion to the quantity of copper of which the solenoid coil is composed. The technical solutions used, in order to reduce the cost of the component, consist in limiting the internal hydraulic sections of the discharge valve: this however entails the disadvantage of a potential fouling and blocking of the solenoid valve component, during its operating life, for example if occasional impurities are contained in the water contained in the tank of the machine.

Aims and summary of the invention

The present invention essentially proposes to solve the aforesaid drawbacks, by means of a machine for the preparation of beverages of the type indicated at the beginning of reduced cost, of reliable operation and having simplified electrical wiring. A further object of the invention is to provide a valve particularly suitable for use in a machine of the type indicated. These and other purposes are achieved, according to the invention, by a machine having the characteristics indicated in claim 1. Likewise, the subject of the present invention is a drain valve and valve unit for use in a machine for preparing beverages of the type defined above, as indicated in claims 10 and 14. Advantageous embodiments of the invention are indicated in the sub-claims. The claims are an integral part of the technical teaching provided herein in relation to the invention.

Brief description of the drawings

Further objects, characteristics and advantages of the invention will appear from the following detailed description, carried out purely by way of limiting example with reference to the attached drawings, in which:

Figure 1 schematically illustrates a machine for preparing beverages according to the prior art;

Figure 2 shows a basic hydraulic diagram of a machine for preparing beverages according to possible embodiments of the present invention;

Figure 3 illustrates, through a schematic perspective view, a valve unit usable in accordance with the present invention; And

Figures 4, 5 and 6 illustrate, by means of respective schematic axial sections, a valve assembly which can be used in accordance with the present invention.

Description of preferred embodiments

The following description illustrates various specific details aimed at an in-depth understanding of the embodiments. The embodiments can be made without one or more of the specific details, or with other methods, components, materials, etc. In other cases, structures, materials or operations known or evident to the skilled person are not shown or described in detail, to avoid obscuring the various aspects of the embodiments. Reference to "an embodiment" within this description means that a particular configuration, structure or feature described in relation to the embodiment is included in at least one embodiment. Therefore, phrases such as "in one embodiment", "in various embodiments", and the like, possibly present in different places of this description are not necessarily referred to the same embodiment. Furthermore, particular conformations, structures or features can be combined in any suitable way in one or more embodiments. The references used here are for convenience only and therefore do not define the scope of protection or the scope of the forms of implementation.

In Figure 1, M generally indicates a machine for the preparation of beverages made in the past by the Applicant, as previously indicated. The machine M is shown limitedly to one of its hydraulic circuits, of interest for the purposes of understanding the present invention. This machine M has a hydraulic circuit including an infusion unit 1, which from the hydraulic point of view is substantially equivalent to a throttle, for delivering a drink to a cup 2 or the like, for example arranged above a collection tray or drawer DR which is usually equipped with a machine for preparing coffee.

An electric pump 3 has its inlet connected to a water tank 4 by means of a suction duct 5 on which a flowmeter 6, for example of the turbine type, can be interposed to provide electrical signals (impulses) indicative of the flow rate. water sucked in by the pump 3. The pump 3 can be an electric vibration pump, or a pump driven by an electric motor 7, of a per se known type.

The pressurized water emitted from the pump 3 reaches an electric heating device or boiler 8, and from this it proceeds towards the infusion group 1, through a supply line 5 '. Upstream and downstream of the heater device 8 (i.e. between the pump 3 and the device 8, on one side, and between the device 8 and the infusion group 1, on the other side) there are two normally closed unidirectional hydraulic valves, indicated with 9 'and 9 ", suitable to allow a flow of water towards the infusion group 1 when the pressure of the water coming from the pump 3 exceeds a predetermined threshold value, equal for example to 2 bar.

The number 10 indicates a first discharge valve, in the form of a two-way two-position solenoid valve, having the inlet 10IN connected to a duct 11 which extends between the outlet of the pump 3 and the one-way valve 9 '. The output 10OUT of the valve 10 is connected to the tank 4. The valve 10 is of the normally open type.

In the known machine M the infusion group 1 comprises at least two parts la and 1b, at least one of which is movable with respect to the other, and capable of defining an infusion chamber between them, when they are in a closed or close position. As already indicated in the introductory part, a first part is configured for the introduction into the infusion chamber of the heated water necessary for the preparation of the beverage. The second part, on the other hand, defines an accommodation, configured to receive a precursor of the beverage (for example a dose of ground coffee, or a capsule containing this dose of precursor) and to allow the drink to be dispensed from the infusion chamber. With reference to the illustrated example, it is assumed that the aforesaid first and second parts of the group 1 are those indicated with la and 1b, respectively, at least the first part being movable relative to the second part. The second part 1b can be for example in the form of a drawer container or a hose which can be removed from the machine M and repositioned thereon, as previously explained.

The machine M has an actuation system, comprising a fluid actuator, which is controllable to cause at least the displacement of the movable part la of the unit 1 towards the other part 1b, i.e. from an open or spaced position to the aforementioned closed or close position. . The open position of the two parts la, lb of the group 1 is that which allows the loading of the beverage precursor (or its evacuation after a dispensing), while in the closed position part of the water forced by the pump 3 can be fed to the chamber of infusion for the preparation of the drink and its delivery.

In the machine M exemplified, the movement of the part la towards the part 1b is obtained by means of the fluid actuator indicated with 12, which is fed by means of the same pump 3 which feeds the infusion unit 1. In the following it is assumed that the actuator 12 is a hydraulic actuator having a piston which can be displaced under the pressure of a part of the water forced by the pump 3, in contrast to the reaction of one or more return springs or similar elastic elements.

The infusion unit 1 and the relative fluid actuator 12 can be made, for example, according to the technique described in CN 202875026 U.

For this purpose, from the delivery of the pump 3, between the output of the pump 3 and the one-way valve 9 ', a conduit 11 departs, connected to the inlet 10iN of the valve 10', and a conduit 13 in turn branches off from this conduit. for powering the actuator 12. The actuator 12 is therefore substantially powered in shunt or in parallel with respect to the infusion unit 1.

SM indicates a manual selector, of the electromechanical type, which can be switched between an open (or non-dispensing) position and a closed (or dispensing) position. The selector SM is associated with a second drain valve 14, in the form of a two-way mechanical valve with two positions, having the inlet 14IN connected between the one-way valve 9 "and the infusion unit 1, and the outlet 140UT connected to the previously cited collection tray or drawer DR. An electric switch Sw is also associated with the selector SM, adapted to supply to a control unit ECU of the machine M a signal indicative of the position of the selector itself, and therefore of the valve 14.

For the purposes of preparing the beverage, and after having loaded the necessary dose of precursor (for example a capsule) into part 1b of group 1, the user moves the selector SM from the open position (shown in Figure 1) to the closed position. The consequent displacement of the valve 14 (from right to left, referring to figure 1) closes the part of the hydraulic circuit directed to the collection drawer DR. The same movement of the selector SM causes the switching of the switch Sw, which then supplies the control unit ECU with the signal Sin, which is representative of the start of a beverage preparation cycle.

The unit ECU, following the reception of the Sin signal, sends a power signal Sout (for example between 120 and 230 V) to the solenoid 10a of the valve 10. The consequent movement of the valve 10 (from left to right, referring to figure 1), in contrast to the action of a relative spring, therefore closes the part of the circuit between the duct 11 and the tank 4.

At this point the unit ECU commands the activation of the pump 3, which fills the circuit causing an increase in pressure. In particular:

a part of the water forced by the pump 3 can reach - through the pipes 11 and 13 - the actuator 12, with the latter thus causing the passage of part la of the infusion group in its closed or close position relative to part lb ; the water cannot flow from the outlet 10OUT of the valve 10, the latter being maintained by the relative solenoid 10a in the closed condition;

- another part of the water forced by the pump 3 can instead pass through the device 8, in order to be heated, to then reach the group 1 and therefore cause the infusion and dispensing of the drink; the water cannot flow from the outlet 140UT of the valve 14, the latter being in the closed condition.

It should be noted that the actuation of the actuator 12, that is the closing of the group 1, occurs before the water leaving the heating device 8 reaches the group 1. This can be obtained for example by appropriately determining the sections of the ducts of the branch " hot "and of the" cold "branch supplied by pump 3 or, preferably, by suitably calibrating the springs of the one-way valves 9 'and 9".

When the user wishes to interrupt the dispensing of the drink, he returns the selector SM to the initial opening position. Thereby:

moving the mechanical valve 14 to the position of figure 1 will open the part of the circuit between the group 1 and the one-way valve 9 ", that is, it will place this part of the circuit in fluid communication with the outlet 140UT of the valve 14 (as in figure 1) ; the residual hot water present in this part of the circuit will then be discharged into the DR collection container;

following the opening commutation of the switch Sw, and therefore the interruption of the signal Sin, the control unit ECU will deactivate the pump 3 and will interrupt the power supply signal Sout of the solenoid IOa: behind the action of the relative spring, the the valve obturator 10 will then return to its normal open position (as in figure 1), and the cold water present in the part of the circuit given by the pipes 11 and 13 will be able to return to the tank 4 through the outlet 10OUT of the valve 10 (this also in force of the piston retraction caused by the relative spring).

In the machine according to the prior art described above, the drain solenoid valve 10 represents a rather expensive component. In fact, it comprises an excitation solenoid 10a, which must be connected to the control unit ECU of the machine M by means of a suitable electrical line Sout. Furthermore, as indicated in the introductory part of the present description, the need to limit the quantity of copper of which the coil of the solenoid 10a is composed has the consequence that the valve has a reduced mechanical actuation force, and for this reason the hydraulic sections inside the same valve are reduced, typically by about 1 mm in diameter: this circumstance entails the risk of component blocking, for example in the case in which the water forced by the pump 3 contains occasional impurities.

A substantial saving and an improvement in operating performance can be achieved with the solution according to the present invention, possible embodiments of which will now be described with reference to Figure 2. In this figure, parts and elements already described have been attributed again the same reference numbers used previously.

In the machine M according to Figure 2, the discharge valve, indicated as a whole with 10 ', is a valve with hydraulic piloting and a device for controlled tapping of water, such as a self-priming valve, is operatively associated with it. In preferred embodiments, the hydraulically piloted drain valve and the aforementioned tapping device are integrated in a single valve unit, such as that indicated with 20 in Figure 2.

In various embodiments, the valve 10 'is a hydraulically piloted discharge valve which comprises:

a main input 10iN, intended for connection to the part of the circuit dedicated to powering the actuator 12, given by the conduits 11 and 13,

a main output 10OUT, intended to be connected in fluid communication with the tank 4, - an auxiliary input 10DR_iN, intended to be connected to the delivery of pump 3,

- an auxiliary output 10DR-OUT downstream of which the fluid actuator 12 and the infusion unit 1 are intended to be connected in parallel, the latter upstream of the one-way valve 9 'and preferably downstream of a further valve unidirectional 21, e

- a further outlet 25, intended to be placed in fluid communication with a device 22 for the controlled tapping of forced water from the pump 3, preferably represented by a self-priming valve, where this device 22 has an outlet communicating with the tank 4.

As will appear later, the output 25 and the main input 10IN carry out respective piloting of the valve 10 '- indicated respectively with 25p and lOp in the hydraulic diagram of figure 2 - one interposed between the input 10DR-IN and the output 10DR_OUT, to upstream to the one-way valve 21, and the other interposed between inlet 10IN and outlet 10OUT.

In preferred embodiments, the tapping device 22, preferably a self-priming valve, is integrated in the further outlet 25, with the valve 10 'and the device 22 forming an integrated valve assembly 20.

The inlet 10iN and the outlet 10OUT are here defined as "main" as they relate to the main discharge function of the valve 10 '(i.e. the discharge of the supply line of the actuator 12), as well as the hydraulic piloting of one of its parts shutter. On the other hand, the input 10DR_iN and the output 10DR-OUT are here defined as "auxiliary" since they are essentially linked to hydraulic piloting functions in closing the aforesaid obturator member of the valve 10 '.

As will be seen, the arrangement is such that, after the pump 3 is activated for the preparation of a beverage, the hydraulically piloted discharge valve 10 'automatically switches from its normally open condition to the closed condition. Subsequently, once the beverage has been dispensed, the pump 3 is deactivated and, thanks both to the connection 25 to the tapping device 22, and to the presence of the aforementioned opening and closing hydraulic pilots lOp and 25p, respectively, the valve 10 'returns independently to its normal open condition, which allows the water residues present in the part of the circuit relating to the power supply of the actuator 12 to be discharged.

The valve 10 ', or the valve unit 20 which integrates it together with the device 22, has a simplified structure, and neither a solenoid, nor a dedicated electric line, nor any electrical / electronic piloting component is required for its control.

Figure 3 illustrates a possible embodiment of the valve 10 ', or rather of a valve assembly 20, usable in the machine M of Figure 2.

The valve 10 'comprises a hollow body which, in the illustrated embodiment, is formed by two elements 23 and 24, for example in molded plastic material, joined together in a sealed manner, for example by means of a threaded coupling or an additional retaining member , as in the case exemplified.

The element 23 is at least partly substantially cup-shaped, in order to define an internal chamber. At one end of the element 23 the element 24 is sealedly coupled, also at least in part substantially cup-shaped to define its own internal chamber.

In the example illustrated, the element 23 defines a tubular fitting which forms the auxiliary inlet 10DR_IN, a conduit which forms the auxiliary outlet 10DR_OUT, as well as a tubular fitting 25 to which the tapping device 22 is intended to be associated. of its inlet, the duct that makes up the auxiliary outlet 10DR-OUT defines two fittings, one that forms the duct 11 and the other, indicated with 5 ", for connection to the infusion unit 1. Preferably, the fittings that make the duct 11 and the fitting 5 "each comprise parts tightly coupled together, in order to allow the one-way valves 21 and 9 'to be housed inside them, respectively.

As will be seen below, the inlet 10DR_IN, the outlet 10DR-OUT and the fitting or duct 25 are in fluid communication with the chamber inside the element 23. Still referring to the example of Figure 3, from the element 24 it is possible to tubular fittings branch off which make up the main entrance 10IN and the main exit 10OUT. Also in this case, as will be seen below, the inlet 10IN and the outlet 10OUT are in fluid communication with the chamber inside the element 24.

In various embodiments, the inlet of a further substantially T-shaped fitting, indicated by 11 'in figure 3, is associated with the fitting that forms the duct 11, the two opposite outlets of which define a first connection 11a', for the fluidic connection to the duct 13 (see also figure 2), and a second connection 11b ', for connection to the main inlet 10iN, by means of a tube not represented in figure 3 but schematized in figures 5 and 6, where it is indicated with 11 and'.

The internal structure of the valve assembly is visible in figures 4-6. In these figures, 26 indicates the already mentioned internal chamber of the element 23, substantially cylindrical, in fluid communication with the pilot inlet 10DR_IN, here in a lateral or radial position with respect to the same chamber 26. The chamber 26 has a first lateral port 26a, which constitutes the inlet of the duct which forms the outlet 10DR-OUT, in correspondence with which there is an obturator 21a of the one-way valve 21. The one-way valve 21 prevents the potential backflow of cold water, coming from the duct 13 relative to the actuator 12. In addition, its calibration allows the complete actuation of the valve 10 'during the operation of the pump 3. Said valve 21 further comprises a calibrated helical spring 21b, able to constantly stress the obturator 21a in the respective closed position of light 26a. The valve 21 is preferably housed within the fitting that makes up the duct 11: the latter, as already mentioned, preferably includes two tubular parts that are coupled together in a sealed manner, in order to allow the assembly of the valve 21.

Downstream of the one-way valve 21, the fitting 5 "departs from the fitting that makes up the duct 11, which in various embodiments houses the one-way valve 9 ', including the relative obturator 9a and calibrated spring 9b. Also the fitting 5 ", as already mentioned, preferably includes two tubular parts tightly coupled to each other, in order to allow the assembly of the valve 9 '.

The chamber 26 has a second lateral opening 26b (Figure 6) in correspondence with which the tubular fitting or duct 25 extends outwards which, in preferred embodiments, houses the tapping device 22 inside.

In preferred embodiments, the device 22 is a self-priming valve. This valve 22 can be of any type known in the field for use in combination with small pumps, particularly vibration pumps. In the embodiment example illustrated in Figure 6, the valve 22 essentially consists of a closure element 22a of the fitting 25, defining a through hole 22b which forms an outlet of the valve 22. The hole 22a has a smaller diameter than the axial cavity 25a of the fitting 25, in which a piston 22d is slidably housed, having a portion of narrow section at its end facing the hole 22b. The proximal end of a helical spring 22e is fitted onto this portion of restricted section. In the illustrated example, the distal end of the spring 22e abuts the closing element 22a which defines the outlet 22b. The spring 22e is set to keep the end of the narrow section of the piston 22d in a spaced position with respect to the hole 22b, without however occluding the opening 26b. The piston 22d has a portion of diameter substantially corresponding to that of the cavity 25a, provided on the surface with recesses which in any case allow a modest passage of liquid between the port 26b and the hole 22b. It should be noted that, even in the condition of maximum compression of the spring 22e, the piston 22d may not cause the closure of the hole 22b, so that the valve 22 always allows a leak of liquid, in the presence of pressurized water in the chamber 26 .

The self-priming device 22 that can be used for the purposes of implementing the invention can also be of a different type with respect to the one exemplified here, without prejudice to its functionality, essentially consisting in allowing a modest tapping of liquid from the port 26b, tending to eliminate any air present in the hydraulic circuit downstream of the pump 3 of figure 2.

Again in Figures 4 and 5, 27 indicates the aforementioned internal chamber of the element 24, substantially cylindrical, in fluid communication with the main inlet 10IN of the group 20, here defined by a fitting in a radial position on the element 24. The chamber 27 has a port 27a, here defined centrally on the bottom of the chamber 27, in fluid communication with a fitting which forms the main outlet 10OUT. Preferably, the port 27a is defined in correspondence with a valve seat, preferably formed by a tubular relief of the bottom of the chamber 27.

A shutter member 31 is housed inside the chamber 27. At the lower end of the member 31 there is a closing element 31a, mounted in an axially sliding manner in the chamber 27 and capable of closing the outlet port 27a, while its upper end there is a membrane element, indicated as a whole with 31b, whose outer edge 31c is constrained in a respective seat, not indicated, defined between two interface surfaces of the elements 23 and 24. The membrane element 31b can be conveniently formed of elastic or resilient material, such as a rubber or a silicone. Advantageously, the elements 31a and 31b can be formed in a single body, but the case of a shutter member 31 formed in several parts assembled together is not excluded from the scope of the invention.

In various embodiments, the membrane element 31b is configured to urge the closing element 31a towards the opening position of the outlet port 27a of the chamber 27. Moreover, in possible variants of embodiment, on the bottom of the chamber 27, the first end of a calibrated helical spring (schematically exemplified only in figure 2, where it is indicated with 28) can abut around the seat referred to in the port 27a, the second end of which is instead associated with the member 31, for example abutting against a relative seat or abutment defined on the member 31, lower than the membrane element 31b (for example defined by an annular widening of the element 31a).

As will be seen, the shutter member 31 is used for the hydraulic piloting of the valve 10 '.

The outer edge 31c of the membrane element 31b and the relative seat are sized to ensure the seal of liquid towards the outside of the valve body. As can be seen, the two chambers 26 and 27 are substantially coaxial with each other and sealed apart from each other by means of the membrane element 31b of the member 31.

The operation of the valve assembly 20 of Figures 3-6 is as follows.

For the purpose of preparing a beverage, the necessary dose of precursor of the beverage, for example ground coffee contained in a capsule, is introduced into the infusion group 1 (Figure 2), all according to methods known per se. For example, the user removes the aforementioned drawer or hose container which defines the part 1b of the infusion chamber and places the dose of precursor therein, preferably contained in a capsule or pod. The container or hose can then be repositioned on the machine in the predefined position, with the compartment for the precursor axially aligned with part la.

The user then controls the dispensing of the beverage, with the consequent start-up of pump 3. Unlike the known technique shown in Figure 1, in this case the command to start dispensing can be given by switching a simple switch or button. electric (not shown), therefore without the need for an electromechanical selector of the type indicated with SM in figure 1.

During the first delivery phases, the water arriving from the pump 3 reaches the chamber 26 through the pilot inlet 10DR_IN, gradually filling it. The pressure in the chamber 26 increases progressively, counteracted by the calibration of the spring 21b, allowing the membrane 31b to prevent the communication of fluid between the chambers 27 and the outlet 10OUT. When the water pressure in the chamber 26 overcomes the relatively low setting of the spring 21b of the one-way valve 21, the corresponding obturator 21a moves, opening the port 26a. In this way the water forced by the pump 3 can pass through the 10DR-OUT outlet and then divide into two flows:

- a first flow passes through the fitting that forms the duct 11, up to the T fitting indicated with 11 ', e

- a second flow which, passing through the opening indicated with 11a only in figure 4, can pass through the fitting 5 ".

The aforesaid first flow reaches the fitting 11 'and then passes into the duct 13, through the relative connection 11a', to then reach the hydraulic actuator 12. The supply of the actuator 12 determines the displacement of the chamber part la in the closed position , relative to part 1b (see figure 2). As previously mentioned, in the case of use of a capsule containing the dose of precursor of the beverage, the part la of the group 1 can include a series of points which cause the perforation of an end wall of the capsule itself. On the other hand, if necessary, also the part 1b of the group 1 can be provided with similar points, suitable to cause the perforation of the opposite end wall of the capsule, under the thrust operated on the same capsule from the part la which moves towards the part 1b (it should be noted however that the invention can also be used in combination with machines whose infusion unit is designed to receive pre-perforated capsules, or filter paper pods, or directly the precursor in powder or granular form) .

In this phase, part of the water of the aforementioned first flow can fill the connection 11b ', the pipe 11le' and the main inlet 10IN, but without being discharged towards the tank 4: this in consideration of the fact that in this phase the the opening 27a of the chamber 27 is kept closed by the shutter member 31, as explained below.

The second flow mentioned can pass through the fitting 5 "when the water pressure in the port 11a overcomes the calibration of the spring 9b of the one-way valve 9 ', and the relative obturator 9a opens the port 11a. In this way, the second flow can reach the heating device 8, pass the one-way valve 9 "and then reach the infusion unit 1, in order to allow the beverage to be dispensed into the container 2.

Note that, given the presence of the one-way valves 9 'and 9 "(see also figure 2), whose calibration value is preferably higher than that of the one-way valve 21, the first flow will reach the actuator 12 and cause the its activation before the second flow can reach the brew group 1.

The pressure of the water in the chamber 26 determines the bending of the membrane element 31b of the member 31 (also overcoming the calibration of the spring 28 possibly present in the chamber 27). This bending causes the translation of the closing element 31a until it comes into contact with the upper edge of the tubular relief in which the opening 27a is defined, which is then closed. During this initial phase, the self-priming valve 22 in fluid communication with the chamber 26 ensures the presence of pressurized water in the same chamber, while at the same time allowing to limit the presence of air in the circuit downstream of the pump 3. The modest quantity of water passing through the self-priming valve 22 is clean water and can therefore be made to flow towards the tank 4, through the fitting 25, to which a suitable pipe can be connected.

During the dispensing of the beverage, part of the pressurized water present between the connection 11b 'of the fitting 11' and the tube 11 '(figures 5-6) can reach the whole of the chamber 27, through the main inlet 10iN . This water cannot flow through the port 27a, given the closing condition of the latter, by the action of the shutter member 31. Therefore, the pressure created in the chamber 27 tends to act in opening on the member 31 (in addition to the action of the spring 28 possibly present in the chamber 27): this condition does not however allow the opening of the port 27a, since the force acting on the pressure (and of the possible spring 28) in the chamber 27 does not equal or constrain the pressure present in the chamber 26. Likewise, the water in the chamber 27 cannot reach that contained in the chamber 26, given the insulating action between the chambers 26 and 27 operated by the membrane element 31b of the organ 31. In this phase, the self-priming 22 continues to operate as described above.

At the end of the delivery, the pump 3 is deactivated by the operator again switching the aforementioned electric switch or button. In this way, the self-priming valve 22 ensures a sudden drop of the pressure in the chamber 26 and at the pilot inlet 10DR_IN. On the other hand, the one-way valves 21 and 9 '(and 9 ") can close again, thanks to the action of the relative springs 21b and 9b.

The drop in pressure in the chamber 26 causes the stress on the membrane element 31b of the member 31 which separates the two chambers 26 and 27 to cease - by means of the pilot 25p of Figure 2: in this way the member 31, pushed by the pressure of the chamber 27, by means of the relative piloting 10p of figure 2 (and by the spring 28 possibly present in the chamber 27), can translate in the opposite direction to the previous one thereby allowing the closing element 31a to return to the initial position of opening the opening 27a of the chamber 27. The translation of the member 31, that is the reverse bending to the previous one of the membrane element 31b, is preferably limited by a mechanical limit switch, here represented by the proximal end of a central axial relief 26c of the room 26.

In this condition, the main outlet 10OUT is now in fluid communication, through the chamber 27, with the main inlet 10iN, and therefore with the actuator 12, through the pipe 11e ', the connection 11b' of the fitting 11 ' and the pipe 13. The water present in the part of the circuit relating to the supply of the actuator 12 can thus flow through the main outlet 10OUT towards the tank 4. In this phase, therefore, the water present in the duct 13 follows a path inverse to the previous one, in this also favored by the retraction of the piston of the actuator 12, stressed in this direction by the relative spring. The part la of the infusion group 1 then returns to the respective open or spaced position with respect to the part lb.

Any residual water present between the infusion group 1 and the one-way valve 9 "may contain residues of the beverage and / or its precursor (for example coffee powder): this water can be evacuated by pravity towards a container for the collection of the type of the one indicated with DR in figure 2. This can be obtained, according to methods known per se, by suitably arranging the part la of the group 1 and the part of the relative supply duct between the one-way valve 9 "and the group itself ( for example an inclined or substantially vertical arrangement).

As can be seen, the operation of the valve 10 'is essentially based on the differential pressures which are established at different times in the chambers 26 and 27 through the respective pilots 25p and 10p of figure 2, particularly during and after the activation of the pump 3. In particular, after the pump 3 is activated for the preparation of the beverage, the obturator element 31 passes from the open condition to the closed condition, due to the effect of the water pressure in the pilot chamber 26, determined by the actuation of the pump itself. Subsequently, after the pump 3 is deactivated at the end of the dispensing of the beverage, the pressure in the pilot chamber 26 decreases as a result of the tapping action determined by the valve 22 or similar device, thereby allowing the shutter member 31 to return to the open condition, due to the effect of the pressure transmitted by the pilot lOp and present at the inlet 10iN, or in the chamber 27 (in addition to the force of the spring 28 possibly present in the chamber 27).

From the above description the characteristics of the present invention are clear, as well as its advantages. Among these should be emphasized:

the proposed solution is decidedly economical, in view of the elimination of a solenoid, and therefore of the cost related to its copper coil, necessary for the operation of the traditional drain solenoid valve;

- the cost of the solution is further reduced since neither an electromechanical selector of the type indicated with SM in figure 1, nor a specific electrical wiring for connection and control of the hydraulically piloted drain valve are required; the control electronics of the machine are also simplified, since there is no need for an electronic piloting component, such as a triac, typically necessary in the case of the discharge solenoid valves according to the known art;

- the fact that the piloting of the discharge valve is of the hydraulic type allows to increase the passage sections of the parts of the circuit relating to the fluid actuator, which can be brought from a value of about 1 mm in diameter, traditionally provided in the case of use of solenoid valves, about 2 mm in diameter, in the case of the present invention;

the realization of the discharge valve, even when integrating the self-priming valve or similar device for controlled tapping, is simple and economical; to this is added the fact that the self-priming valve usable for the purposes of the implementation of the invention can be of a commercially available type, and therefore of limited cost; the correct priming of the machine pump is of course also guaranteed, given the elimination of air from the machine circuit;

the operation of the discharge valve is reliable and substantially independent both from the calibration of the springs of the usual one-way valves provided on the supply branch of the brewing unit, and from the pressure generated in the aforementioned branch from the quantity of beverage precursor present in the brewing chamber (the which pressure is also a function of the quantity of ground coffee, for example what is contained in a capsule); the valve intervention time is also fast and guaranteed;

- the hydraulic piloting of the discharge valve has no negative effects on obtaining the correct pressures in the brewing chamber of the machine.

Naturally, the embodiments and the details of construction may be widely varied with respect to what has been described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention as defined in the attached claims.

As mentioned, the construction of the shutter member 31 can be different from that - exemplified here - with a single body that defines the closing element 31a and the membrane element 31b. For example, in possible variants of embodiment, the member 31 can include an intermediate body of plastic material interposed between the elements 31a and 31b, configured as distinct parts; such an intermediate body can possibly provide a stop for the upper end of the spring 28 possibly present inside the chamber 27, tending to normally stress the shutter member in its condition in which the opening 27a is open.

In the previously described embodiments, the hydraulically piloted drain valve 10 'and the device 22, such as a self-priming valve, are integrated in a single valve unit 20. However, it should be noted that this is not an essential feature of the invention. , given that - in possible variants of embodiment - the device 22 can also be mounted in a remote position with respect to the valve 10 ', downstream of the fitting indicated with 25, for example connected to the latter by means of a suitable conduit. Similarly, hydraulic connection components that make up the pipes or fittings il, il ', 5 "could be configured as distinct parts with respect to the valve, connected in fluid communication with the outlet 10DR-OUT.

In other embodiments of the invention, the necessary seal between the chambers 26 and 27 could be determined, instead of by a membrane element of the type indicated with 31b, by means of one or more rings that surround the outside of the member 31, particularly around to its closing element of the type indicated with 31a, for example of the o-ring type, which slide on the internal surface of the chamber 27. The use of a membrane element must in any case be considered preferable, since it allows to increase the reliability of the valve in view of the absence of sealing elements subject to sliding.

The invention has previously been exemplified with reference to its use in combination with an actuator intended to move a part of the infusion unit of the machine M. The discharge valve described is however capable of being used for feeding and / or discharging. of similar fluid actuators - particularly hydraulic actuators in which the return movement of a relative piston is determined by elastic means - which are used on the preparation machine for other purposes, particularly to cause a displacement of one or more members of the preparation machine other than a part of its infusion group (for example for the purpose of switching a release system of a door of the machine itself).

Claims (15)

CLAIMS 1. A machine (M) for preparing beverages, in particular espresso coffee, comprising a hydraulic circuit including - an infusion group (1), comprising at least a first and a second part (la, lb) which can define an infusion chamber between them, when they are in a closed or close position, at least the first part (la) of the infusion group (1) being mobile with respect to the second part (lb), a fluid actuator (12), particularly a hydraulic actuator which can be increased to cause at least a displacement of the first part (la) of the brewing unit (1) towards the second part (1b), - a water tank (4), a pump (3) having the inlet connected in fluid communication with the water tank (4) and the outlet or delivery connected in fluid communication with the infusion unit (1) and with the fluid actuator ( 12), at least one normally closed one-way hydraulic valve (21) interposed between the pump (3) and the infusion unit (1), to allow a flow of water towards the infusion unit (1) when the water pressure emitted by the pump (3) exceeds a substantially predetermined threshold, - a heating device (8) to heat the forced water from the pump (3) towards the brewing group (1), and a normally open discharge valve (10 ') having a main input (10IN), connected to the fluid actuator (12), a main outlet (27a, 10OUT), connected to a collection room, particularly the water tank (4), - a shutter member (31) interposed between the main inlet (10IN) and the main outlet (10OUT), able to assume an open condition and a closed condition, in which it allows and respectively prevents a flow of fluid between said main inlet (10IN) and said main output (10OUT), the shutter member (31) being optionally urged by a spring (28) towards the open condition; the machine (M) being characterized by the fact that the discharge valve (10 ') is a hydraulically piloted valve, which also comprises a piloting chamber (26), for the hydraulic piloting of the shutter member (31), an inlet auxiliary (10DR_IN) of the piloting chamber (26), connected to the pump delivery (3), and an auxiliary output (26a, 10DR-OUT) of the piloting chamber (26), connected to the brewing unit (1) and to the fluid actuator (12), so that the water emitted by the pump (3) passes through the pilot chamber (26) before reaching the infusion unit (1) and the fluid actuator (12), respectively , the discharge valve (10 ') also having a further outlet (26b, 25) of the pilot chamber (26), connected in fluid communication with a device (22) for tapping water from the pilot chamber (26) , particularly towards the water tank (4), the provision being such that: after the pump (3) is activated for the preparation of the beverage, the shutter member (31) passes from the open condition to the closed condition due to the effect of the water pressure in the pilot chamber (26) determined by the actuation of the pump ( 3), and after the pump (3) is deactivated at the end of the beverage dispensing, the pressure in the pilot chamber (26) decreases due to the tapping caused by the tapping device (22), thereby allowing the shutter member (31) to return to the open condition due to the pressure present at the main inlet (10IN) of the discharge valve (10 '). The machine according to claim 1, wherein the tapping device (22) comprises a self-priming device. The machine according to claim 1 or claim 2, wherein the discharge valve (10 ') and the tapping device (22) are integrated in a single valve assembly (20). The machine according to any one of claims 1-3, wherein the discharge valve (10 ') comprises a further chamber (27) which communicates with the main inlet (10XN) and the main outlet (10ουτ), the further chamber (27) having a bottom in which a seat is defined of valve (27a); the shutter member (31) comprises a membrane element (31b) to which a closing element (31a) is associated which can cooperate with the valve seat (27a), the membrane element (31b) sealingly separates the pilot chamber (26) from the further chamber (27) and is elastically flexible to allow the movement of the closing element (31a) associated with it relative to the valve seat ( 27a), between the closing element (31a) and the bottom of the further chamber (27) the said moila (28) being optionally operationally interposed. The machine according to claim 4, wherein the closure element (31a) and the membrane element (31b) are formed in one piece. The machine according to any one of claims 1-5, wherein a further one-way valve (9 ') is arranged between the one-way valve (21) and the heating device (8). The machine according to any one of claims 1-6, in which a first connection (5 ") and a second connection (11, 11) are provided downstream of the auxiliary outlet (26a, 10DR_OUT) of the pilot chamber (26) ') for the parallel fluidic connection of the infusion group (1) and the fluid actuator (12), respectively. 8. The machine according to claim 7, wherein the second fitting (11, 11 ') has a first and a second outlet (11a', 11b '), the first outlet (11a') being connected in fluid communication to the fluid actuator (12) and the second outlet (11b ') being connected in fluid communication with the main inlet (10XN) of the discharge valve (ΙΟ'). The machine according to claims 6 and 7, in which the at least one one-way valve (21) is associated with the second connection (11, 11 ') and the further one-way valve (9') is associated with the first connection (5 "), the first and the second fitting preferably each comprising two parts tightly coupled together, between which the relative one-way valve is arranged. 10. A normally open drain valve (10 ') for a beverage machine having a main inlet (10iN), intended for connection with a fluid actuator (12) of the machine (M), a main outlet (27a, 10OUT), intended for connection to a collection room, particularly a water tank (4) of the machine (M), a shutter member (31) interposed between the main inlet (10IN) and the main outlet (10OUT), able to assume an open condition and a closed condition, in which it allows and respectively prevents a flow of fluid between said main inlet ( 10IN) and said main outlet (10OUT), the shutter member (31) being optionally urged by a relative spring (28) towards the open condition; the discharge valve being characterized in that it is a hydraulically piloted valve (10 ') which further comprises a pilot chamber (26) for the hydraulic piloting of the shutter member (31), an auxiliary inlet (10DR_iN) of the pilot chamber (26), intended for the fluidic connection with the delivery of a pump (3) of the machine (M), an auxiliary outlet (26a, 10DR-OUT) of the pilot chamber (26), intended for the fluidic connection with an infusion unit (1) and with the fluid actuator (12) of the machine (M), in such a way whereby the water emitted by the pump (3) passes through the pilot chamber (26) before reaching the infusion unit (1) and the fluid actuator (12) of the machine (M), respectively, a further outlet (26b , 25) of the pilot chamber (26), intended to be connected in fluid communication with a device (22) for tapping water from the pilot chamber (26), particularly towards the water tank (4) of the machine (M). The valve according to claim 10, integrating the tapping device (22) to form a valve assembly (20), the tapping device preferably comprising a self-priming device. The valve according to claim 10 or claim 11, comprising a further chamber (27) communicating with the main inlet (10IN) and the main outlet (10OUT), the further chamber (27) having a bottom in in which a valve seat (27a) is defined, and in which: the shutter member (31) comprises a membrane element (31b) to which a closing element (31a) is associated which can cooperate with the valve seat (27a), between the closing element (31a) and the bottom of the further chamber (27) the said spring (28) being optionally operationally interposed, the membrane element (31) sealingly separates the pilot chamber (26) from the further chamber (27) and is elastically flexible to allow the movement of the closing element (31a) associated with it relative to the valve seat ( 27a). The valve according to any one of claims 10-12, further comprising, downstream of the auxiliary outlet (26a, 10DR-OUT) of the pilot chamber (26), a first fitting (5 ") and a second fitting (11 , 11 ') for the parallel fluidic connection of the infusion unit (1) and the fluid actuator (12), respectively. An integrated valve assembly (20) for use in a beverage preparation machine, comprising a hydraulically operated drain valve (10 ') according to any one of claims 10-13 and a device for tapping water (22). The valve assembly (20) according to claim 14, wherein the water tapping device (22) is a self-priming device.